US7307701B2

Method and apparatus for detecting a moving projectile

Summary by NHIP

Laser Projectile Detector

The method pivots a housing on a post to maintain a horizontal 360° azimuthal laser beam while detecting moving projectiles via Doppler shift analysis. The system uses a two-dimensional detector array receiving mixed sum and difference frequencies from a reference beam, with signals processed by circuits performing filtering and fast Fourier transformation.

Claim Score by NHIP

Read claim 1, the broadest

Abstract

An apparatus includes a transmitter portion which transmits a defined beam of eyesafe laser energy, a receiver portion which receives reflected energy from the beam, and a further portion which analyzes information in the received energy so as to detect the presence of a moving projectile.

US7307701B2, drawing sheet 1
Sheet 1 of 4

Term

Term ended

Expired 30 October 2023, 2.9 years ago.

  1. Priority and filed
  2. Granted
  3. Expired
  4. Today

21 claims: 5 independent, 16 dependent

  1. 1
    Broadest claimClaim Score 58, broad(NHIP)A method comprising:pivotally coupling a housing to a post;transmitting a defined beam of eyesafe laser energy by a window disposed on an upper end of the post, said beam having an azimuth angle of 360°;receiving reflected energy from said beam onto a detector stored in the housing, the detector having a two-dimensional array of detector elements and, in response, forming a two-dimensional image representing a contiguous 360° azimuthal view on the detector;analyzing information in said received energy by an electronic circuit contained in the housing so as to detect the presence of a moving projectile;and tilting, using a weight disposed on a lower end of the post, the post relative to the housing such that angular movement of the housing allows the beam to remain in a generally horizontal orientation.
  2. 10
    An apparatus comprising:a gimbal that pivotally couples a housing to a post having an upper end and a lower end, the lower end being coupled to a weight;a transmitter portion which transmits a defined beam of eyesafe laser energy through a window disposed on the upper end of the post, said beam having an azimuth angle of 360°;a receiver portion which receives reflected energy from said beam onto a detector stored in the housing, the detector having a two-dimensional array of detector elements and, in response, forming a two-dimensional image representing a contiguous 360° azimuthal view on the detector;and a further portion which analyzes information in said received energy by an electronic circuit contained in the housing so as to detect the presence of a moving projectile.
  3. 19
    A method comprising:pivotally coupling a housing to a post;transmitting a defined beam of eyesafe laser energy by a window disposed on an upper end of the post, said beam having an azimuth angle of 360°;receiving reflected energy from said beam onto a detector stored in the housing, the detector having a two-dimensional array of detector elements and, in response, forming a two-dimensional image representing a contiguous 360° azimuthal view on the detector;detecting the presence of a moving projectile by detecting a Doppler shift in said received energy by an electronic circuit contained in the housing;and tilting, using a weight disposed on a lower end of the post, the post relative to the housing such that angular movement of the housing allows the beam to remain in a generally horizontal orientation.
  4. 20
    A method comprising:pivotally coupling a housing to a post;transmitting a defined beam of eyesafe laser energy by a window disposed on an upper end of the post throughout a predetermined beam azimuth angle;receiving reflected energy from said beam onto a detector in the housing, the detector having a two-dimensional array of detector elements and, in response, forming a two-dimensional image representing a contiguous field of regard on the detector;analyzing information in said received energy by an electronic circuit contained in the housing simultaneously throughout the field of regard so as to detect the presence of a moving projectile;and tilting, using a weight disposed on a lower end of the post, the post relative to the housing such that angular movement of the housing allows the beam to remain in a generally horizontal orientation;wherein the field of regard defines a contiguous azimuthal extent that is to be analyzed for the presence of a moving projectile and wherein the beam azimuth angle is substantially equivalent to the field of regard.
  5. 21
    An apparatus comprising:a gimbal that pivotally couples a housing to a post having an upper end and a lower end, the lower end being coupled to a weight;a transmitter portion that transmits a defined beam of eyesafe laser energy through a window disposed on the upper end of the post, said beam having a beam azimuth angle;a receiver portion that receives reflected energy from said beam onto a detector stored in the housing, the detector having a two-dimensional array of detector elements and, in response, forming a two-dimensional image representing a contiguous field of regard on the detector simultaneously throughout the field of regard;and a further portion that analyzes information in said received energy by an electronic circuit contained in the housing so as to detect the presence of a moving projectile;wherein the field of regard defines a contiguous azimuthal extent that is to be analyzed and wherein the beam azimuth angle is substantially equivalent to the field of regard.